Fractionation of lanolin oil



Filed Nov. 18, 1955 INVENTOR.

CONRAD J. SUNDE wirr.

BY E

ATTORN EY United States Patent i N. l., a corporation of New Jersey Application November 18, 195s, seal No. 392,897 1o claim-s. (ci. 26o-428.5)

This invention relates" generally to the manufacture of an oil from lanolin, particularly a cosmetic grade lanolin oil, suitable for* blending with mineral oil. More particularly, the invention relates to afmethodl for fractionating wool grease, crude or refined, into a liquid lanolin fraction miscible in substantially all proportions with mineral oil and a4 hard lanolin fraction of relatively high meltingvpoint and waxy appearance. n

The method'involves mixing the Wool grease with'between 2 and5 parts of a solvent comprising at least 20% byv volume of hydrocarbons having 5 to 9 carbon atoms per molecule and at least 40% by volume of at least one member selected from aV group consisting ofthose'ketones not heavier than isobutyl ketone; increasingl the' tempera ture" of thernxture to produce a clear solution (ordinarily betweenl 80 and 100 F., depending directly upon the density of the wool grease and inversely on the solvent ratio); cooling the mixturev slowly at a rate ofl not greater thanlS F. per hour until a heavy fraction` is precipitated, leaving in solution a light fraction of oil having the prop# erty' that its cloud point is not higher than about\70'F,. and preferably not higher than about 67 F. The light fraction is recovered from the solution and hasl the unique property of being miscible with mineraly oil toy a degree not hitherto known with lanolin or a lanolin fraction'. The cloud point referred to is that determined by the American Society for Testing Materials Method of Test forrCloud and Pour Points D 97-47.

Wool grease is obtained from the scouringliquors of sheeps wool. As the term is used herein, itincludes reli'ne'dwoolv fat (U. S'. Pharmacopoeia), neutral wool grease and degras. Wool grease isfnotclassifiablewith glyceride oils, ordinary fats, or what are usually called greases or waxes. It is a complex mixture of esters of heavy alcohols and acids originatingin the sheeps wool; it is to be sharply distinguished from the raw scouring liquor from which it is recovered by the elimination of substantially all liquids and solid matter foreign to the fat-like wool' grease.

Wool grease has many properties which make it useful in the field of cosmetics, for example in creams, `skin oils, lipticks. However, because of its value, it is desirable to form a commercial mixture of lanolin in a mineral oil vehicle. Unfortunately, it has not heretofore been possible to prepare commercially satisfactory mixtures because substantial parts of the wool grease would not go into solution, or having gone in, could not be relied upon to remain in under ordinary conditions of usage. Many previous methods of refining wool grease or of separating it into light and heavy fractions have been tried in order to obtain a fraction suitably miscible with mineral oil. For the most part, these were entirely unsuccessful and in those cases in which a miscible fraction was recovered, thevyield was so low as to make the-process uneconornic. Itis the object of this invention to provide a methodjfor separatingffromvwool grease substantiallyall constituents readily miscible with mineral oil.-

A specific embodiment of this invention is shown in the 2,758,125 Fatented Aug. 7, 1956 2.. accompanying drawing' which illustrates a reineryV suitable for practicing the method disclosed.

Inthe drawings shown a batch type plant which may conveniently be operated on approximately a 24-hour cycle basis.-

Fora charging' period of about an hour, a charge 0f wool grease, heated to'ab'out 100 F. to make is flowable, enters'the'system through line 10 and is mixed in crystallizer tank 1l with solvent enteringthrough line 12. Ternperature conditions within the crystallizer l1 are controlled by means ora-brine coil 13 supplied through lines 14 and 1S. At first, hotbrine (a temperature of 140 F. isftypical) is circulated through coil 13' to gradually warm up themixture of solvent and wool grease in crystallizer il until a clear solution isproduced. In commercial practice, it is'convenient to warm the crystallizer in every case tov about'l 100 F. since experience shows that this willinsure the formation of a clear solution `in` l5 minutes or 1/2 hour.` It will be understood, of course, that temperatures of or 90 F. may be'employed ifV higher solvent ratios',- or' a longer settling time is used. However, it is impractical, under commercial conditions, to allow many hours to pass for the formation of a solution at temperatures of 70 F. or the like; At the same time, the mixture' is continuously stirred with mild agitation with mixerl 16J` Preferably, mixer" I6 is a paddle-type mixer offab'out' 5 feetindiam'eterroftated'at about 3 R. P. M. withina' crys'tallizer batch of 1000' gallons. After the passage ofyabout 15 minutes at100 F. with a'mixt'ure ratioA of about three parts solvent to one part of wool grease: charge,` a'clear` solution isfo'rmed. lf less solvent is em'pleyed', laslightly longer solution time may be reqiretfl.v Cold'brineVv ('"35 FI) is now introduced in a slowlyv increasing proportion in the brine vcirculating through coilv 1:3' so" asto produce a steady decline in tempe'r'at'ure' within crystallize' 1-1. Thetemperature of the bri'nef'passingthroug-lr coil 13 during the cooling period should never be more than`15 F. c older than the solventwool' grease mixtureand preferably not more than about 10 F. l colder. rI-'h'e'secohd important condition is that the rat'f of"c`o`olingV the' mixture yrn'u'st not exceed 15 F. per hourand ai preferred ligure in most cases would be about 10 Flp'er hour. The slow cooling rate is" desirable in order to form' asE few crystal nuclei as possible, allowing for the maximurirA crystal growth,v so as to produce a precipitate characterized `b`y` porosity to produce a lte'r. cake capable-of ready' filtration. Ordinarily, cooling may be discontinued at a temperature between about 0 F. to -25 F. depending uponprelir'ninary tests of samples of the specific batch to determineprecisely at which cooling temperature a fraction is reached, which has the requirdproperties. The test property, -which is thekey to proper manipulation of the process is the cloud point of the'light fraction. A 'Ihepreferrfed-cloud point for the light fraction is about6'6' F., butvit may be as'high as 70 F. in the'cas of sor'ne` wool grease' as this temperature is quite critical and its possible variation in exceptional cases'up toward-them limit can only be determined for specific batches of wool grease by runningI tests with mineral oil mixtures. The lower limit for cloud point is not a rigid one; butA isdtermined by economic yield. Too low,L a cloud point'in'di'cates" that some of the valuable light `fraction has :been allowedto escape with the heavy fraction?.

A minimum cloudpoirit,y for purposes-of good economic yield would ordinarily be above 60 F., but preferably even higher. A preferred rangev of'cloud points for the light fraction may be setY 'up-i between 62 F. and 67 F. Afteravperiod ofab'out 14 hours of coolingin crystallizer l1; thecold-rnixture, cloudy but owable, and containing` between l5 andi-20% crystallized' matter, is withdrawn from' crystallizer 11 at'17 and pumped by means of a piston filter feed pump 18 at a pressure gradually increasing to about 50 lbs. per square inch through line 19 to a filter 20 of the jacketed plate and frame press type.

After a period of about one hour or somewhat less, the filtrate leaves filter 20 by way of line 21 and passes to decolorizing tank 22, in which the filtrate encounters a mass of loose activated charcoal granules and decolorizing clays, introduced by way of a port 23 before the running of a batch. Filtrate is pumped from the bottom of tank Z2 by pump 24 through lines 25 and 26, valve 27 being open and valve 28 being closed, for a period of about one hour, i. e. until the desired lightness in color is achieved. The circulating filtrate and entrained solids pass through a heater 29 to maintain an optimum decolorizing temperature not so high as to injure the lanolin, i. e. between about 130 F. and about 150 F.

After adequate circulation, valve 27 is closed, valve 28 is opened, and filtrate and solids are diverted to filter 30, which is preferably comprised of -mesh stainless steel screen upon which a layer (usually about 1/8 inch thick) of filter aid has been deposited. The filter aid is generally diatomaceous earth laid down on the screen as a suspension in previously filtered liquid. If color is not important, the decolorizing steps may be omitted.

Decolorizing filtrate leaves filter 30 by way of line 31 and is separated into a lanolin oil product and solvent vapor by evaporation in lanolin oil evaporator 32. The lanolin oil is withdrawn at 33 and the solvent vapor flows through line 34 to a water cooled condenser 35. Most of the solvent is condensed, ows down to solvent receiver 36 by way of line 37, then through line 38 and pump 39 to a deicer 40 (having brine lines 41 and 42); and from deicer 40 through line 43 to solvent storage 44.

Residual vapor rising from condenser 35 through line 45 encounters brine condenser 46 so that additional solvent is condensed. Remaining uncondensables are exhausted to the atmosphere through line 47 by means of steam vacuum jet 48. Evaporator 32 is heated by steam line 49. The hard lanolin wax precipitate is recovered from filter 20, after the batch has been filtered and filtrate removed through line 21, by heating filter 20 with warm brine introduced at lines 50 and 51. (The same lines may be used during filtering for cold brine to keep the filter at low temperatures.) Also, warm solvent (the same as that employed during crystallization) is introduced by pump 52 and line 53 from wash tank 54, which is provided with a steam heating coil 55. A slurry of melted filter cake and wash solvent is thus washed from filter 26 through line 56 to wash tank 54.

Throughout both filtration and washing periods, liquid drainings in filter 20 should be pumped by pump 57 through line 58 to wash tank 54.

Of course, both decolorizing tank 22 and Wash tank 54 should be provided with suitable vent condensers, valves, drains, etc. conventional with such tanks in this art.

In wash tank 54, the slurry of precipitate and solvent is heated to get all lanolin into solution and at the same time is mixed with a filter aid such as diatomaceous earth (at temperatures of about 50 F. to 80 F.). The solution is pumped through line 59 by pump 60 to filter 61 (which is preferably similar to filter 30) and then through line 62 to hard lanolin evaporator 63 (steam heated by steam line 64).

Hard lanolin product is withdrawn through line 65 in a hot liquid condition. Vapors leave evaporator 63 through line 66, are condensed by water condenser 67 and brine condenser 68. The condensed solvent flows through line 69 to solvent receiver 70, and then by line 71 through pump 39 to deicer 40, returning from there to solvent storage.

The most elective solvent was a mixture of 53.3% methyl ethyl ketone and 46.7% heptane, and the best solvent ratio was 3 parts by weight of solvent to one part of wool grease. However, other hydrocarbons and other ketones having a reasonably low boiling point were also tried and found satisfactory within the certain limits; isobutyl ketone is about the highest molecular weight ketone which appears suitable.

The hydrocarbons above the peak efficiency of mixture and solvent ratio is not greatly affected by shifting to other hydrocarbons and ketones except that the preferred solvent ratio does shift slightly when proportions of hydrocarbon and ketone are varied. As the hydrocarbon percentage increases, the solvent ratio may be reduced a little; as the hydrocarbon percentage decreases, the solvent ratio goes up somewhat faster. However, the range of 2/1 to 5/1 weight ratio of solvent to oil covers the practical range for all the solvent mixtures within the scope of this invention. Viewed as a curve plotted against all the variables of solvent composition and yield, the peak eliiciency may be said to fall always between 2.5/1 and 3.5/1 and practical operability between 2/ 1 and 5/1. However, as solvent ratio goes up, the size of the equipment goes up so economic considerations put a limit. But even more important, both yield and cloud point go up and with higher solvent ratios there is greater and greater danger of producing an extract with too many components immiscible in mineral oil.

The proportions of the solvent components may also be varied within a limited range. The higher the ketone proportion the lower the cloud point of the extract fraction and the lower the yield; the higher the hydrocarbon fraction, the higher the yield and the higher the cloud point since cloud point of an extract obtained with this solvent mixture has been found to correlate closely with the property of miscibility with mineral oil. In fact, increasing yield point meets declining miscibility at a point which very nearly corresponds to a cloud point of about 66 F. for most wool greases. However, wool grease is immensely variable; moreover, end use considerations may indicate a need for greater miscibility, or economic considerations may indicate a need for higher yield, even if miscibility is reduced, so cloud points as high as 70 F. may be tolerated and as low as 62 F. may be commercially practiced.

Date of actual runs made at various solvent ratios and with the preferred solvent mixture of about 54% methyl ethyl ketone and 46% heptane produced the following results:

Lbs. Lbs. Per- Cloud Crystal- Yield, Grease Run Sol- Lano- Ratio cent Point, lization Per- No. vent lin MEK F. Tempercent ature Lbs. Lbs. Per- Cloud Crystal- Grease Run Sol- Lano- Ratio cent Point, llzation Yield,

No. vent lin MEK F. Tern- Percent perature amples fall within the scope of the invention, but they are not within the scope of the preferred species because too small a percentage of methyl ethyl ketone either reduces the yield or raises the cloud point. Too high a percentage of methyl ethyl ketone either raises the solvent grease ratio or lowers the cloud point and the yield.

It is to be understood that the above data is by way of example only and that the invention extends to the scope set forth in the specification in connection with the description of the specific embodiment. Various other solvent mixtures can be used within the scope of the invention. Benzol, for example, may be used with acetone or methyl ethyl ketone as described. Solvent-oil ratios and other operating conditions may be varied Within the scope of the invention as described.

I claim:

to crystallize from said solution a heavy fraction and leaving in said solution a fraction having a cloud point between 62 F. and 67"Y F.; continuously mildly agitating said solution during cooling and cooling it without contact with any cooling agent more than F. lower in temperature; and filtering and recovering a liquid lanolin fraction from the filtrate.

4. A method for separating from wool `grease a liquid lanolin fraction miscible in substantially all proportions with mineral oil, which includes the steps of: mixing wool grease having not more than 1% by weight of water content with a solvent comprising between 40 and 70% by weight of an open chain ketone having up to 9 carbon atoms per molecule and between 60 and 30% by weight of a hydrocarbon having 5 to 9 carbon atoms per molecule, the weight ratio of said oil having between about 2 to l and about 5 to l; heating the resulting mixture until a j clear solution is produced; slowly cooling said mixture at 1.- A method for separating from wool grease a liquid y lanolin fraction miscible in substantially all proportions with mineral oil, which includes the steps of: mixing wool grease having .not more than 1% by weight of water content with a solvent comprising at least by weight of a hydrocarbon having `from 5 to 9` carbon atoms per molecule and at least 40% by weight of an open chain ketone having up to 9 carbon atomsv per molecule, the weight of said solvent to said oil being about 2 to l and about 5 to l; heating the resulting mixture until a clearl solution is produced; slowly cooling said heatedmixture at a rate not higher than 15 F. per hour to a temperature suiiciently low to precipitate all components of saidwool grease from solution, except the liquid having a cloud point not higher than about 70 F. and recovering said liquid lanolin from said solution.

2. A method for separating from woo] grease a liquid a rate not higher than 15 F. per hour to a temperature between 10 F. and 35 F. to a crystallization temperature at which the cloud point of material remaining in solution falls below 70 F.; contacting said solution with charcoal; and recovering a liquid lanolin fraction from said solution.

5. A method for separating from wool grease a liquid lanolin fraction readily miscible with mineral oil, which includes the steps of: heatingsaid wool grease to a temperature above 120 F. and mixing it with a solvent comprising about to 70 Weight percent of an open chain ketone having up to 9 carbon atoms per molecule and 60 to 30 weight percent of a hydrocarbon having from 5 to 9 carbon atoms per molecule, the weight ratio of said solvent to said oil being about 2 to 1 and about 5 to l;

heating the resulting mixture to a temperature of between 90` F. and 120 F.; slowly cooling said heated mixture at a rate not higher than 15 F. per hour to a lanolin fraction miscible in substantially all proportions,`

with mineral oil, which includes the steps of mixing wool.`

grease having not more than 1% by weight of water content with a solvent comprising at least 20% by weight of a hydrocarbon having from 5 to 9 carbon atoms per molecule and at least 40% by weight of an open chain ketone having up to 9 carbon atoms t per molecule, the Weight ratio of said solvent to said oil being between about 2 to 1 and about 5 to 1; heating the resulting mixture until a clear solution of said wool grease in said solvent is obtained; slowly cooling said heated mixture at a rate not higher than 15 F. per-hour to a temperature suiiciently low to precipitate all components of said wool grease from solution, except a liquid lanolin fraction of between about to about 70% by weight of said wool grease, said lanolin fraction having a cloud point not higher than about F. and recovering said liquid lanolin from said cool solution.

. 3. A method for separating from'wool grease a liquid lanolin fraction miscible in substantially all proportions with mineral oil, which includes the steps of: mixing wool grease having not more than 1% by weight of water content with a solvent comprising at least 20% by weight of hydrocarbon having from 5 to 9 carbon atoms per mole-l cule and at least 40% by weight of an open chain ketone 1 having up to 9 carbon atoms per molecule, the weight ratio of said solvent to said oil being between about 2 to l and about 5 to 1; heating the resulting mixure until a clear solution is produced; slowly `cooling said heated mixture at a rate not higher than 15 F. per hour to a temperature between about 10 F. and about 35 F.

temperature between l0 F. and 35 F. to crystallize high melting point materials and leave in solution a liquid lanolin fraction having a cloud point of less than 70 F.; and recovering a liquid lanolin from said solution.

6. A method is described in claim. 3, in which said ketone is acetone.

7. A method is described in claim 3, in which said ketone is methyl ethyl ketone.

8. A method is described in claim 3, in which said hydrocarbon is hexane.

9. A method is described in claim 3, in which said hydrocarbon is heptane.

l0. A method for separating from wool grease a liquid lanolin fraction readily miscible with mineral oil, which includes the steps of: mixing Vwool grease having not more than 1 weight percent water content with a solvent comprising about 50 to 55 weight percent methyl ethyl ketone and about 50 to 45 percent heptane in weight ratio of between 2.5 and 3.5 parts of solvent to one part of wool grease; heating the resulting mixture to a temperature of about F. to 110 F.; slowly cooling said mixture at a rate not higher than about 10 F. per hour to a temperature between 0 F. and 25 F.; continuously gently agitating said mixture during cooling and preventing said mixture from contacting any surface more than 15 F. cooler than the temperature of the mixture; withdrawing an extract solution after sucient solids have precipitated to leave in said extract solution a liquid lanolin having a cloud point between 62 F. and 67 F.; and recovering from said extract solution a liquid lanolin readily miscible with mineral oil.

References Cited in the le of this patent Gillespie: Wool Wax, 1948, page 25. 

1. A METHOD FOR SEPARATING FROM WOOL GREASE A LIQUID LANOLIN FRACTION MISCIBLE IN SUBSTANTIALLY ALL PROPORTIONS WITH MINERAL OIL, WHICH INCLUDES THE STEPS OF: MIXING WOOL GREASE HAVING NOT MORE THAN 1% BY WEIGHT OF WATER CONTENT WITH A SOLVENT COMPRISING AT LEAST 20% BY WEIGHT OF A HYDROCARBON HAVING FROM 5 TO 9 CARBON ATOMS PER MOLECULE AND AT LEAST 40% BY WEIGHT OF AN OPEN CHAIN KETONE HAVING UP TO 9 CARBON ATOMS PER MOLECULE, THE WEIGHT OF SAID SOLVENT TO SAID OIL BEING ABOUT 2 TO 1 AND ABOUT 5 TO 1; HEATING THE RESULTING MIXTURE UNTIL A CLEAR SOLUTION IS PRODUCED; SLOWLY COOLING SAID HEATED MIXTURE AT A RATE NOT HIGHER THAN 15* F. PER HOUR TO A TEMPERATURE SUFFICIENTLY LOW TO PRECIPITATE ALL COMPONENTS OF SAID WOOL GREASE FROM SOLUTION, EXCEPT THE LIQUID HAVING A CLOUD POINT NOT HIGHER THAN ABOUT 70* F. AND RECOVERING SAID LIQUID LANOLIN FROM SAID SOLUTION. 